I know what you are thinking. It isn't Darwin's birthday yet. However, as Doc Brown once said, "You aren't thinking 4 dimensionally". It is now midnight in Downe, England. The town where Darwin did his seminal work on natural selection. So from a certain point of view it is Darwin's B-day. That point of view just happens to be the UK right now. So, Happy Birthday Darwin!
To celebrate, here is a link to Darwin's work on Geology during his voyage on the Beagle. Plenty of nifty maps and drawings, and excerpts of text. Here is an example of some of his geology. This is a stratigraphic section of the banks of Santa Cruz, in Patagonia.Happy birthday Darwin. The celebrations, I'm sure, will continue.
Edit: Looks like I was beaten to the punch. Chris M. over at Pools and Riffles posted a similar idea weeks ago.